Variance is the number that standard deviation is afraid to show in public — the same spread information, but in squared units nobody can picture. Square the distances of each value from the mean, average those squares, and you get variance: squared dollars, squared points, squared inches. A dataset of 2, 4, 6 has a variance of 4 (square units), which becomes a friendly standard deviation of 2 once you take the square root.

So why does variance exist at all? Because it has beautiful math. Variances of independent quantities add together — the variance of a sum is the sum of the variances — which makes it the workhorse of probability theory, finance, and quality engineering. A bolt manufacturer in Michigan tracking diameter variance of 0.0004 mm² knows instantly whether the process is drifting, long before any single bolt looks wrong.

This calculator computes it from up to five values. Enter your numbers in the Value boxes under Data Values, and it returns the variance — the squared spread that statisticians actually compute with, even when they report its square root.

With the pre-filled defaults — Value 1 2, Value 2 4, Value 3 4, Value 4 4, Value 5 5 — the Variance Calculator returns Mean 3.8000, Population Variance (σ²) 0.960000, Sample Variance (s²) 1.200000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.